The invention relates generally to systems having a high-voltage energy source and, more particularly, to a method and apparatus of providing a high-voltage diagnostic tool for x-ray imaging systems.
Typically, in an x-ray imaging system such as a computed tomography (CT) imaging system, an x-ray source emits a fan-shaped beam toward a subject or object, such as a patient or a piece of luggage. Hereinafter, the terms “subject” and “object” shall include anything capable of being imaged. The beam, after being attenuated by the subject, impinges upon an array of radiation detectors. The intensity of the attenuated beam radiation received at the detector array is typically dependent upon the attenuation of the x-ray beam by the subject. Each detector element of the detector array produces a separate electrical signal indicative of the attenuated beam received by each detector element. The electrical signals are transmitted to a data processing system for analysis which ultimately produces an image.
The x-ray source, or x-ray tube, is connected to a high-voltage (HV) generator or tank via high-voltage cables or lines, wherein the HV generator provides the x-ray tube with voltage sufficient to emit an x-ray beam toward the subject. On occasion, x-ray tubes fail when in use in the imaging system due to high-voltage instability, thereby necessitating service to the imaging system by a trained technician. This high-voltage instability results in a high-voltage discharge or arcing between the electrodes of the x-ray tube or between an electrode and ground, where these high-voltage discharges are commonly referred to in the art as “spits.” The “spits” can cause not only failure of the x-ray tube itself, but also failure of attached electrical components.
Typically, the technician will perform a no-load test using a “dummy plug” in place of an x-ray tube. The dummy plug is designed to maintain the insulation integrity of the system, which is generally done by leaving the pins of the dummy plug open or shorted to provide adequate insulation for the system, yet not provide the load characteristics of an x-ray tube. The use of a dummy plug in this manner allows the technician to distinguish whether the system failure is attributable to a faulty x-ray tube or high-voltage instability in the HV generator and/or high-voltage cables. Based on the results of this test, the technician typically decides whether it is desired to either simply replace the x-ray tube or to perform a more in-depth analysis of the HV generator using, for instance, another x-ray tube.
However, while the no-load test using a dummy plug may distinguish whether the failure is attributable to the x-ray tube or the HV generator, the test typically does not allow the technician to diagnose or detect specific problems that may be related to the x-ray tube, HV generator, or high-voltage cables. For instance, kV regulation errors related to the HV generator would not be detectable when using the dummy plug, as the dummy plug does not mimic the load characteristics of an x-ray tube. As such, a technician typically cannot diagnose specific issues related to the HV generator while in the field. Thus, by using a dummy plug, solutions proposed by the technician in correcting the HV generator or x-ray tube issues may not address the actual failure mode of the system.
In order to diagnose a system problem, a technician may use a second known-good x-ray tube which may be connected to the generator to test the system. However, if the problem being diagnosed is in the high-voltage generator, then the technician may unknowingly put the second x-ray tube at risk. Thus, if the second x-ray tube is damaged in the process, it may cost additional time, money, and inconvenience to both the technician and the owner of the system before the problem can be properly diagnosed.
Therefore, it would be desirable to design an apparatus and method of providing a high-voltage diagnostic tool for x-ray imaging systems that is capable of providing load conditions for an HV generator during troubleshooting, and is further capable of allowing a technician to diagnose specific problems related to HV generator and/or tank/generator integration issues.